Maintaining very small ecosystems

You know you could launch a constant stream of small
ecosystems, say a 1000ft diamenter ocean system filled
with fertilzers kelps and different fish from an L5.
They could sit like a cup in a solar mirror saucer.
Maybe a small solar powered rocket to adjust the
systems orbit. The L5 colony could use these as also a
form of radiation shielding. When the fish have grown
the ecosystem comes back from it's small jaunt in the
L5 gravity basin of to be harnessed and sent off
again.
Makes you want to start singing, "The Circle Of Life".
best regards
Pete